The "psychological immune system" is a shorthand term used to encompass a number of biases and cognitive mechanisms that protect the subject from experiencing extreme negative emotions.[1][2] They achieve this by ignoring, transforming or constructing information, making the existing state of affairs more bearable while decreasing the appeal of the alternatives.[3] They operate largely or entirely outside conscious awareness. Psychologists Daniel Gilbert and Timothy D. Wilson coined the term, using the biological immune system as a metaphor for these processes.[4]

Bias in affective forecasting

The mechanisms of the psychological immune system act without conscious awareness, so people usually fail to anticipate its effects. This is one reason why people are surprisingly poor at affective forecasting: predicting how they will feel in possible future situations. People typically overestimate the extent of the effect that a negative event, such as the death of a relative or a job loss, will have on them.[4][1]

↑ 4.04.1includeonly>Gertner, Jon. "The Futile Pursuit of Happiness", New York Times, September 7, 2003. Retrieved on 2009-08-29. “Gilbert says. "We've used the metaphor of the 'psychological immune system' -- it's just a metaphor, but not a bad one for that system of defenses that helps you feel better when bad things happen."”